The present invention relates to a method of monitoring manufacturing apparatus for monitoring the operating state of each of a plurality of manufacturing apparatus used sequentially to manufacture a plurality of products of different processing priorities or different types in a manufacturing line, e.g., a manufacturing line for electronic devices such as Large Scale Integration (LSI). More particularly, it relates to a method of monitoring manufacturing apparatus for evaluating, when the operation of any of the manufacturing apparatus is halted due to trouble occurring therein or maintenance thereof, influence exerted by the operation halt on the manufacturing state of each of products.
In a conventional method of monitoring manufacturing apparatus, influence exerted by an operation halt of each of the manufacturing apparatus on the manufacturing state of each of products (hereinafter referred to as halt influence) has been evaluated by monitoring an operation halt period of the manufacturing apparatus (a period between an operation halt and reoperation) or the number of operation halts.
Specifically, in a manufacturing line composed of a plurality of manufacturing apparatus, the operation halt period or the number of operation halts of each of the manufacturing apparatus is stored in a database based on apparatus halt data (the operating state of each of the manufacturing apparatus or the cause of the operating state) transmitted from each of the manufacturing apparatus. The total operation halt period or the total number of operation halts of each of the manufacturing apparatus is calculated on a, e.g., monthly basis and a manufacturing apparatus having a longer total operation halt period or a larger total number of operation halts has been evaluated to have received greater halt influence.
In short, the conventional method of monitoring manufacturing apparatus has evaluated the halt influence based only on the length of the operation halt period of the manufacturing apparatus and on the frequency of operation halts thereof.
In a typical manufacturing line, however, an apparatus operability differs from one manufacturing apparatus to another. The apparatus operability is defined herein as a proportion of a period during which a manufacturing apparatus operates for product processing (hereinafter referred to as a product processing period) to a given period of time. If the period during which the manufacturing apparatus is not in operation during the given period is assumed to be an apparatus idle time, the apparatus operability can be given by, e.g., the following equation:
xe2x80x83Apparatus Operability=Product Processing Period/(Product Processing Period+Apparatus Idle Time).
Accordingly, a higher apparatus operability indicates a higher utilization factor (a higher degree of busyness) of the manufacturing apparatus.
However, since the conventional method of monitoring manufacturing apparatus has evaluated the halt influence based only on the length of the operation halt period of the manufacturing apparatus or on the frequency of operation halts thereof, the following problems arise if the conventional method of monitoring manufacturing apparatus is implemented with respect to a manufacturing line for electronic devices or the like in which the apparatus operability differs greatly from one manufacturing apparatus to another.
(1) Because of the different operabilities of the manufacturing apparatus, it is difficult to precisely evaluate the halt influence based on the length of the operation halt period of each of the manufacturing apparatus. For example, even when a manufacturing apparatus has a long operation halt period, the halt influence is negligible if the degree of busyness of the manufacturing apparatus is low during the operation halt period. Conversely, even when a manufacturing apparatus has a short operation halt period, the halt influcence is great if the degree of busyness of the manufacturing apparatus is high during the operation halt period.
(2) Because of the different operabilities of the manufacturing apparatus, it is difficult to precisely evaluate the halt influence based on the frequency of operation halts of the manufacturing apparatus. For example, even when a manufacturing apparatus has a large number of operation halts, the halt influence is negligible if the degree of busyness of the manufacturing apparatus is low during each of the operation halt periods. Conversely, even when a manufacturing apparatus has a small number of operation halts, the halt influcence is great if the degree of busyness of the manufacturing apparatus is high during each of the operation halt periods.
In view of the foregoing, it is therefore an object of the present invention to enable precise evaluation of halt influcence exerted by an operation halt of any of manufacturing apparatus on the manufacturing state of each of products.
To attain the object, a first method of monitoring manufacturing apparatus according to the present invention assumes a method of monitoring manufacturing apparatus for evaluating, when operation of any of the manufacturing apparatus used to manufacture a plurality of products is halted, influence exerted by the operation halt on a manufacturing state of each of the plurality of products as a halt influence by monitoring an operating state of each of the manufacturing apparatus, the method comprising the step of: evaluating the halt influence based on a difference between a first number of processing waiting products and a second number of processing waiting products, the first number of processing waiting products being a number of products of the plurality of products which are in a processing waiting state in the manufacturing apparatus at a time at which the operation of the manufacturing apparatus is halted or at a time antecedent thereto, the second number of processing waiting products being a number of products of the plurality of products which are in the processing waiting state in the manufacturing apparatus at a time at which the manufacturing apparatus is reoperated after the operation thereof is halted or at a time posterior thereto.
In accordance with the first method of monitoring manufacturing apparatus, the halt influence is evaluated based on the difference between the first number of processing waiting products before the operation of the manufacturing apparatus is halted and the second number of processing waiting products after the manufacturing apparatus is reoperated. Since the halt influence is evaluated by using the change in the number of processing waiting products during the operation halt period of the manufacturing apparatus, the halt influence can be evaluated in consideration of the busyness of the manufacturing apparatus during the operation halt period thereof. This allows precise evaluation of the halt influence even in a manufacturing line for electronic devices or the like in which busyness differs greatly from one manufacturing apparatus to another.
In the first method of monitoring manufacturing apparatus, the halt influence is preferably judged to be greater as a value obtained by subtracting the first number of processing waiting products from the second number of processing waiting products is larger.
This allows easy evaluation of the halt influence.
A second method of monitoring manufacturing apparatus according to the present invention assumes a method of monitoring manufacturing apparatus for evaluating, when operation of any of the manufacturing apparatus used to manufacture a plurality of products is halted, influence exerted by the operation halt on a manufacturing state of each of the plurality of products as a halt influence by monitoring an operating state of each of the manufacturing apparatus, the method comprising the step of: evaluating the halt influence based on a difference between a first processing waiting period and a second processing waiting period, the first processing waiting period being a period during which a product of the plurality of products which is processed by the manufacturing apparatus during a given period antecedent to a time at which the operation of the manufacturing apparatus is halted is in a processing waiting state in the manufacturing apparatus, the second processing waiting period being a period during which a product of the plurality of products which is processed by the manufacturing apparatus during the given period posterior to a time at which the manufacturing apparatus is reoperated after the operation thereof is halted is in the processing waiting state in the manufacturing apparatus.
In accordance with the second method of monitoring manufacturing apparatus, the halt influence is evaluated based on the difference between the first processing waiting period before the operation of the manufacturing apparatus is halted and the second processing waiting period after the manufacturing apparatus is reoperated. Since the halt influence is evaluated by using the change in processing waiting period during the operation halt period of the manufacturing apparatus, the halt influence can be evaluated in consideration of the busyness of the manufacturing apparatus during the operation halt period thereof. This allows precise evaluation of the halt influence even in a manufacturing line for electronic devices or the like in which busyness differs greatly from one manufacturing apparatus to another.
In the second method of monitoring manufacturing apparatus, the halt influence is preferably judged to be greater as a value obtained by subtracting the first processing waiting period from the second processing waiting period is larger.
This allows easy evaluation of the halt influence.
A third method of monitoring manufacturing apparatus according to the present invention assumes a method of monitoring manufacturing apparatus for evaluating, when operation of any of the manufacturing apparatus used to manufacture a plurality of products is halted, influence exerted by the operation halt on a manufacturing state of each of the plurality of products as a halt influence by monitoring an operating state of each of the manufacturing apparatus, the method comprising the steps of: calculating a first degree of influence based on a value obtained by subtracting, from a number of products of the plurality of products which are in a processing waiting state in the manufacturing apparatus at a time at which the manufacturing apparatus is reoperated after the operation thereof is halted or at a time posterior thereto, a number of products of the plurality of products which are in the processing waiting state in the manufacturing apparatus at a time at which the operation of the manufacturing apparatus is halted or at a time antecedent thereto; calculating a second degree of influence based on a value obtained by subtracting, from a period during which a product of the plurality of products which is processed by the manufacturing apparatus during a given period posterior to the time at which the manufacturing apparatus is reoperated after the operation thereof is halted is in the processing waiting state in the manufacturing apparatus, a period during which a product of the plurality of products which is processed by the manufacturing apparatus during the given period antecedent to the time at which the operation of the manufacturing apparatus is halted is in the processing waiting state in the manufacturing apparatus; and evaluating the halt influence based on the first and second degrees of influence.
In accordance with the third method of monitoring manufacturing apparatus, the first degree of influence is calculated based on the value obtained by subtracting, from the number of processing waiting products after the manufacturing apparatus is reoperated, the number of processing waiting products before the operation of the manufacturing apparatus is halted, the second degree of influence is calculated based on the value obtained by subtracting, from the processing waiting period after the manufacturing apparatus is reoperated, the processing waiting period before the operation of the manufacturing apparatus is halted, and then the halt influence is evaluated based on the first and second degrees of influence. Since the halt influence is evaluated by using the change in the number of processing waiting products and the change in processing waiting period during the operation halt period of the manufacturing apparatus, the halt influence can be evaluated in consideration of the busyness of the manufacturing apparatus during the operation halt period thereof. This allows precise evaluation of the halt influence even in a manufacturing line for electronic devices or the like in which busyness differs greatly from one manufacturing apparatus to another. This also allows more precise evaluation of the halt influence than in the case where the halt influence is evaluated by using either one of the change in the number of processing waiting products and the change in processing waiting period during the operation halt period of the manufacturing apparatus.
In the second or third method of monitoring manufacturing apparatus, the given period is preferably determined based on a time required for product processing performed by the manufacturing apparatus.
This allows the processing waiting period to be calculated in accordance with the time required for product processing performed by the manufacturing apparatus.
In this case, the given period is preferably determined to be longer as the time required for product processing performed by the manufacturing apparatus is longer.
This ensures the obtention of the processing waiting period.
In the third method of monitoring manufacturing apparatus, the step of evaluating the halt influence preferably includes providing at least one of the first and second degrees of influence with a weight based on a characteristic of the manufacturing apparatus and then evaluating the halt influence by using the first and second degrees of influence with the weight.
This allows the halt influence to be evaluated in accordance with the characteristic of each of the manufacturing apparatus even in a manufacturing line composed of a plurality of manufacturing apparatus of entirely different types, properties, performances, or the like.
In this case, the step of evaluating the halt influence preferably includes, when at least one of the first and second degrees of influence is provided with the weight, providing the second degree of influence with a larger weight as a time required for product processing performed by the manufacturing apparatus is longer.
This allows more precise evaluation of the halt influence.
In the third method of monitoring manufacturing apparatus, the step of calculating the first degree of influence preferably includes calculating the first degree of influence in association with each of priorities with which product processing is performed by the manufacturing apparatus, the step of calculating the second degree of influence includes calculating the second degree of influence in association with each of the priorities, and the step of evaluating the halt influence includes calculating a third degree of influence in association with each of the priorities based on the corresponding ones of the first and second degrees of influence calculated in association with the individual priorities and evaluating the halt influence based on each of the third degrees of influence calculated in association with the individual priorities.
This allows precise evaluation of the halt influence even in a manufacturing line for manufacturing a plurality of products of different processing priorities.
In this case, the step of evaluating the halt influence preferably includes, when the halt influence is evaluated based on each of the third degrees of influence calculated in association with the individual priorities, providing each of the third degrees of influence with a weight according to a height of the corresponding one of the priorities, summing up the third degrees of influence each provided with the weight, and evaluating the halt influence based on the total sum.
This allows more precise evaluation of the halt influence considering actual conditions in the manufacturing line, including the different processing priorities of the individual products.